In recent years, a method of applying ink containing a functional material using an ink-jet head has been widely adopted in the manufacture of electronic devices. An ink-jet head discharges ink toward material to which ink is to be applied, via an extremely small aperture (nozzle) provided in a nozzle plate.
With an ink-jet head of this configuration, when ink is discharged from a nozzle, part of the ink or foreign substance such as dust in the air may adhere to the nozzle plate. If foreign substance adheres to the nozzle plate, ink cannot be discharged from a nozzle appropriately, and accurate ink application cannot be performed.
Thus, a printing apparatus having an ink-jet head is normally provided with a wiping apparatus for removing foreign substance adhering to the nozzle plate (see Patent Literature 1, for example). A wiping apparatus that blows gas at an angle to the nozzle plate is known as a wiping apparatus for removing foreign substance (see Patent Literature 2 through 4, for example).
FIG. 1A is a perspective view of a wiping apparatus disclosed in Patent Literature 2, and FIG. 1B is a cross-sectional view of the wiping apparatus shown in FIG. 1A in the process of wiping nozzle plate 11 of ink-jet head 10. Also, FIG. 2 is a cross-sectional view of a wiping apparatus disclosed in Patent Literature 3 in the process of wiping nozzle plate 11 of ink-jet head 10.
As shown in FIG. 1A, FIG. 1B, and FIG. 2, wiping apparatuses disclosed in Patent Literature 2 and Patent Literature 3 have gas injection aperture 130 that injects gas, and gas suction aperture 150 that sucks in gas. Also, as shown in FIG. 1B and FIG. 2, wiping apparatuses disclosed in Patent Literature 2 and Patent Literature 3 inject gas from gas injection aperture 130 at an angle to nozzle plate 11, and blow away foreign substance adhering to nozzle plate 11. Then the foreign substance that is blown away is sucked in by gas suction aperture 150 to prevent it from being scattered about.
However, when gas is injected at an angle from gas injection aperture 130 as in the wiping apparatuses disclosed in Patent Literature 2 and Patent Literature 3, gas is injected toward the inside of nozzle aperture 13 of nozzle plate 11. When gas is injected toward the inside of nozzle aperture 13, drying of ink 15 inside nozzle aperture 13 is accelerated. As a consequence, nozzle aperture 13 becomes clogged, and ink cannot be discharged from nozzle aperture 13.
A technology is known to inject gas parallel to nozzle plate 11 from gas injection aperture 130, as shown in FIG. 3A and FIG. 3B (see Patent Literature 2, for example), in order to prevent gas from being directed toward the inside of a nozzle aperture.
Furthermore, wiping apparatuses are also known (see Patent Literature 5 through 7, for example) that utilize an orifice effect in order to prevent gas from being directed toward the inside of a nozzle aperture.
FIG. 4 is a cross-sectional view of a wiping apparatus disclosed in Patent Literature 5 in the process of wiping nozzle plate 11 of ink-jet head 10. As shown in FIG. 4, a wiping apparatus disclosed in Patent Literature 5 has gas suction aperture 150 and gas guide section 120 having projections 121.
As shown in FIG. 4, between projections 121 of a wiping apparatus disclosed in Patent Literature 5 and nozzle plate 11, orifice sections 123 are formed where the distance between gas guide section 120 and nozzle plate 11 is smaller. When gas is sucked in from gas suction aperture 150 in a state in which orifice sections 123 are formed, the flow rate of the gas increases in orifice sections 123 due to an orifice effect, and foreign substance and the like adhering to the surface of nozzle plate 11 is blown away. Thus, with a wiping apparatus utilizing an orifice effect, gas is not injected at an angle with respect to nozzle plate 11, so that gas is not directed toward the inside of a nozzle aperture.